Composition Optimization and Microstructure Design in MOFs-Derived Magnetic Carbon-Based Microwave Absorbers: A Review

Abstract

Magnetic carbon-based composites are the most attractive candidates for electromagnetic (EM) absorption because they can terminate the propagation of surplus EM waves in space by interacting with both electric and magnetic branches. Metal-organic frameworks (MOFs) have demonstrated their great potential as sacrificing precursors of magnetic metals/carbon composites, because they provide a good platform to achieve high dispersion of magnetic nanoparticles in carbon matrix. Nevertheless, the chemical composition and microstructure of these composites are always highly dependent on their precursors and cannot promise an optimal EM state favorable for EM absorption, which more or less discount the superiority of MOFs-derived strategy. It is hence of great importance to develop some accompanied methods that can regulate EM properties of MOFs-derived magnetic carbon-based composites effectively. This review comprehensively introduces recent advancements on EM absorption enhancement in MOFs-derived magnetic carbon-based composites and some available strategies therein. In addition, some challenges and prospects are also proposed to indicate the pending issues on performance breakthrough and mechanism exploration in the related field.

Keywords: Composition optimization; EM absorption enhancement; Magnetic carbon-based composites; Metal–organic frameworks; Microstructure design.

Fig. 1

a Crystalline structures of some specific MOFs. Reproduced with permission from Refs. [–27]. Copyright © 2017 WILEY–VCH; 2014 The Royal Society of Chemistry; 2018 American Chemical Society; and 2017 Wiley–VCH Verlag GmbH. b Some advantages of MOFs applied in the field of EM absorption, and c Electromagnetic loss and energy conversion mechanism inside MOFs-derived magnetic carbon-based composites

Fig. 2

a XRD patterns, b field-dependent magnetization curves (inset is a magnification of magnetic hysteresis loops), c Raman spectra of S1-S7, and RL maps of d S1, e S2, f S3, g S4, h S5, i S6, j S7, and k their RL curves with the absorber thickness of 2.0 mm. Reproduced with permission from Ref. [63]. Copyright © 2018 Elsevier Inc

Fig. 3

a Synthetic Scheme for the Preparation of Co/NPC@Void@CI, TEM images of b ZIF-67 and c Co/NPC@Void@CI, and d XRD patterns of samples (inset shows the Raman spectra of Co/NPC and Co/NPC@Void@CI. e EDS line scans of Co/NPC@Void@CI, RL maps and RL curves of f Co/NPC and g Co/NPC@Void@CI. Reproduced with permission from Ref. [77]. Copyright © 2017 American Chemical Society

Fig. 4

a Schematic of the preparation of the NC@NCNTs. SEM images of b NC, c NC@NCNTs-1, d NC@NCNTs-2, and e NC@NCNTs-3. TEM images of f NC and g-i NC@NCNTs-2. RL maps of j NC, k NC@NCNTs-2. Reproduced with permission from Ref. [96]. Copyright © 2021 The Royal Society of Chemistry

Fig. 5

a Schematic process of the fast MOF-based ligand exchange strategy for construction of 3D hierarchical Mo2N@CoFe@C/CNT composites. b–d TEM images of Mo2N@CoFe@C/CNT composites, and e 3D RL map, f RL curves of Mo2N@CoFe@C/CNT at the same thickness of 2 mm. Reproduced with permission from Ref. [105]. Copyright © 2021 Springer

Fig. 6

a Schematic representation of the facile synthesis route of the Fe&TiO2@C. b SEM image and c 3D RL map of Fe&TiO2@C. Reproduced with permission from Ref. [116]. Copyright © 2020 Springer

Fig. 7

a Schematic illustration for the synthetic procedure of hollow Co@NCNs. b RL maps and c charge density map of hollow Co@NCNs-800. Reproduced with permission from Ref. [129]. Copyright © 2021 Wiley–VCH GmbH. TEM images of d NiCo@C-0 and e NiCo@C-2; f 3D RL map of NiCo@C-2. Reproduced with permission from Ref. [134]. Copyright © 2020 Elsevier Ltd

Fig. 8

a Schematic illustration of preparing hollow Co/C microspheres via a MOFs-derived strategy, RL maps of b Co/C and c Co/C-HS-600. Reproduced with permission from Ref. [143]. Copyright © 2018 American Chemical Society. d Illustration for the formation of Ni-MOF hollow spheres with controllable surface architecture. Reproduced with permission from Ref. [145]. Copyright © 2019 American Chemical Society. e Schematic illustration of the formation of Ni/C composites. Reproduced with permission from Ref. [32]. Copyright © 2019 Elsevier B.V

Fig. 9

a Synthesis process of hierarchical Co/C@V₂O₃ hollow spheres. Reproduced with permission from Ref. [104]. Copyright © 2019 Wiley–VCH Verlag GmbH & Co. b Schematic illustration of hollow ZnNiC nano-box preparation, c RL curves and normalized input impedance of ZnNiC-600. Reproduced with permission from Ref. [142]. Copyright © 2020 The Royal Society of Chemistry

Fig. 10

a, b SEM images of MZ700, c 3D RL map of MZ800, d density test of MZ800, e thermal infrared images of MZ800 captured at 30 min, f schematics of the heat transfer mechanism. Reproduced with permission from Ref. [147]. Copyright © 2020 American Chemical Society. g Establishment of the tomato-like hierarchical porous FeCo/C@WC. Reproduced with permission from Ref. [154]. Copyright © 2020 The Royal Society of Chemistry

Fig. 11

TEM images of a CoNi@NG-NCP-30, b CoNi@NG-NCP-60, c CoNi@NG-NCP-90, and d CoNi@NG-NCP-120 (scale bars in the images: 500 nm). Reproduced with permission from Ref. [158]. Copyright © 2018 American Chemical Society. e Synthetic processes of the Co–C/Co₉S₈ composite, TEM images of f ZIF-67/Co₉S₈-3 and g Co–C/Co₉S₈-3, and h RL map of Co–C/Co₉S₈-3. Reproduced with permission from Ref. [163]. Copyright © 2018 Springer

Fig. 12

a Schematic illustration for the formation process and the synthetic mechanism of NC@Co/NC carbon nanocages, b, c 3D RL map and RL map of NC@Co/NC carbon nanocages. Reproduced with permission from Ref. [179]. Copyright © 2020 Elsevier B.V. d Schematic illustration for the synthesis process of hollow CoMo@HNCP polyhedron, e RL values of CoMo@HNCP. Reproduced with permission from Ref. [178]. Copyright © 2020 Elsevier Ltd. f Schematic formation process of the composites. Reproduced with permission from Ref. [182]. Copyright © 2020 Elsevier B.V.